Diverticular disease

A spectrum of manifestations associated with colonic diverticulosis. Protrusions of the colonic mucosa through the muscularis layer of the colon where the vasa recta enter the bowel wall.

Epidemiology

• Thought to be mainly a disease of the modern world - related to dietary changes following the industrial revolution
• Increases with age, relatively rare in young adults
  • Seen in 40% of people 50-60yo
  • Seen in >60% of people >80yo
• <5% of patients with diverticulosis will ever get diverticulitis
• Most common cause for lower GIT bleeding (20-40% of all LGIB)

Risk factors

Modifiable

• • Dietary factors
    • Western diet high in red meat, fat and refined grains
    • High-fibre diet (fruit vegetables, whole grains) reduces risk
    • Nuts, seeds and popcorns does not increase risk
  • Central obesity
  • Smoking
  • Active lifestyle is protective

Non-modifiable

• • Scleroderma - can cause wide-mouthed diverticula - not necessarily same pathophysiological process as standard diverticulosis

Pathophysiology

• Diverticula - saccular outpouching of the bowel wall
  • Vast majority in the colon are false diverticula containing only the mucosa and muscularis mucosae
• Formed by herniation associated with zones of increased pressure within the colonic lumen
  • Hypertrophy of the muscular layers of the colon wall
  • Narrowed lumen (especially sigmoid)
  • Disordered colonic motility
• Classically formed on the mesenteric side of the colonic wall, where vasa recta traverse through the muscular layer to provide blood to the mucosa
• Sigmoid and descending colon most common areas, and rectum not affected
• Right-sided diverticulosis
  • Common in Asian countries but rare in the West
  • Managed same as left sided
• Complications
  • Diverticulitis
    • Diverticulum blocked by fecalith or inspissated waste
    • Leads to stasis and bacterial overgrowth, inflammation, and increased pressure within the diverticulum
    • Can lead to ischaemia and micro-perforation
  • Bleeding
    • See LGIB topic
  • Obstruction (chronic stricture)

Presentation

• Diverticulitis
  • Classically LLQ pain, fever, obstipation
  • Localised tenderness and mild distension
  • Check for mass (phlegmon)
  • Rectal bleeding is rare - consider ischaemic colitis or IBD
  • SUDD (symptomatic uncomplicated diverticular disease) - clinically diverticulitis, without imaging findings - seems to overlap with IBS
    • Difficult to differentiate from smouldering diverticulitis (usually CT inflammation and elevated calprotectin) and IBS
    • No defined treatment pathway

Differential diagnosis

• Segmental colitis associated with diverticulitis
  • Stasis/ischaemia in the same region of bowel as diverticula
  • Seems to pretty much the same as diverticulitis clinically, but will look different on colonoscopy (sparing of orifices, as opposed to either complete resolution of inflammation or orifices being the focus of infection)
• Rectal diverticula - rarely symptomatic
• Giant Colonic Diverticula
  • >4cm diameter
  • Arises from antimesenteric border of sigmoid colon in >90% of cases
  • Best treatment would be partial colectomy with primary anastomosis - diverticulectomy carries a high risk of blow-out

Investigation

• CT with IV contrast and blood tests
• CT may not be truly necessary in a patient with classic presentation and fairly well
• Be very careful of flexible sigmoidoscopy in the acute setting - can result in worsening perforation

Classification

• Ambrosetti CT classification
  • Moderate diverticulitis - localised sigmoid wall thickening, pericolic fat stranding
  • Severe diverticulitis - abscess, extraluminal air, extraluminal contrast
• Modified Hinchey classification system - operative classification really, and more useful in the severe cases
  • 0: mild clinical diverticulitis
    • No fat stranding
  • 1a: confined pericolic inflammation - phlegmon
    • Colonic wall thickening and pericolic fat stranding
  • 1b: confined pericolic abscess (within sigmoid mesocolon)
  • 2: pelvic, distant intra-abdominal or intra-peritoneal abscess
  • 3: generalised purulent peritonitis
    • Mortality 6%
  • 4: faecal peritonitis
    • Mortality 35%
• CT can't really distinguish between grade 3 and 4 - usually decided in the operating room

Management - elective diverticular disease

Lifestyle interventions

• • High fibre diet (>30g per day) - high in fruits, vegetables, whole grains - this might prevent the initial disease, but does this really reduce further attacks once diverticulosis is present? No evidence at the moment.
  • Lots of water
  • Avoid foods high in fat
  • Quit smoking
  • Lose weight
  • Reduce meat intake
  • It is completely unproven that avoiding seeds, corn and nuts helps in any way

Elective surgery for patients with prior diverticular attack

• • Base recommendation on patient factors, not number of attacks
  • Following first episode of acute uncomplicated diverticulitis, 10-35% will have another episode
  • After more episodes, the chance of recurrence increases significantly
  • Recurrences in general tend to follow the severity of the initial episode
  • Complicated recurrence after recovery from uncomplicated episode is actually rare (6%), even in young patients - young age is not an indication for surgery necessarily
  • Should be done 6+ weeks down the track
  • Firm indications for colectomy:
    • Fistula
    • Obstruction
    • Stricture
  • Relative indications for colectomy:
    • Mesocolic abscess >5cm and pelvic abscess treated medically generally need definitive surgical resection due to recurrence rate >40%
    • Patients requiring percutaneous drainage are more likely to require more interventions in the future - consider elective colectomy
    • Immunosuppressed patients have a lower threshold for elective surgery, but no firm data on where exactly that threshold lies. Some say after first episode, others say wait.
  • Surgery is sigmoid colectomy
    • Proximal margin should be in soft pliable bowel, but not necessarily removing all proximal diverticula
    • Distal anastomosis should be in upper rectum

Management - acute diverticulitis

Uncomplicated diverticulitis

• • May not be a need for antibiotics in acute uncomplicated diverticulitis in healthy patients. Studies not yet showing any significant difference in outcome or complication rate between observation/Abx.
  • No way of predicting adverse outcomes - antibiotics does not prevent complication in high-risk patients
  • Admit if:
    • Immunocompromise
    • Intolerant to oral intake
    • Sepsis (WCC > 13.5)
    • Lack of social support
    • Frailty or comorbidity
    • Pain
    • No improvement with adequate treatment at home
  • Analgaesia
  • Abx
    • Has not been shown to accelerate recovery or prevent complications or subsequent surgery
  • Altered diet - clear fluids, followed by low-residue diet until the inflammation subsides
  • If no improvement after 72 hours in hospital, consider repeating CT
  • If no improvement after another 48 hours, start considering semi-elective resection
  • Group of patients who immediately flare up again when the antibiotics are stopped - start considering resection if this happens twice

Hinchey 1a

• • Admit, IV Abx
  • Re-scan if deterioration or worsening bloods

Micro-perforation

• • A few localised gas bubbles on CT, either locally or under the diaphragm. In the absence of peritonism or other indicators of sepsis, should be treated medically. 19% progress to abscess.

Hinchey 1b or 2 (localised abscesses)

• • Medical management and IR drainage if amenable (often defined as >3cm). If they deteriorate or fail to improve within 3-4 days, surgery is likely indicated.
    • Leave abscess drain in place until <30mL per day
  • Antibiotic therapy alone is generally sufficient for abscess <3cm, but should be a prolonged course
  • Large abscesses that can't be reached percutaneously could be considered for laparoscopic drainage/lavage
  • Generally recommend elective surgery after recovery

Hinchey 3 or 4

• • Seen at presentation as sepsis, generalised peritonitis and free air in setting perforated diverticulitis
    • Stoma marking early
  • Life-threatening emergency requiring surgical exploration
    • Goals - control source of infection and wash out the contamination
    • Default operation is Hartmann's procedure
    • If Hinchey 4 is found at operation, have to do Hartmann's
    • Reasonable in some selected patients to start off with a laparoscopic lavage and upgrade to Hartmann's if difficult or signs of Hinchey 4. Results in lower stoma rates, but higher rates of ongoing sepsis and re-operation. It does often delay the operation to a later date when the patient is in better condition, so could be worthwhile from that perspective.
      • Don't mobilise the colon, don't go poking around looking for the perforation
      • Irrigate all four quadrants and leave a large drain
      • These patients should improve after 24-48 hours - if not, book for resection
    • If the patient is not unwell, and can tolerate the longer operation, could do a primary anastomosis with loop ileostomy. There is, however, plenty of evidence that reversal rate is higher with primary anastomosis, with no increase in mortality or morbidity, when done by an experienced surgeon. Patient needs to be able to survive a leak and be in good general condition. Much better in Hinchey 1 and 2 disease.
  • In a stable patient with radiological pneumoperitoneum, without diffuse peritoneal findings, you can try to convert an emergent operation to a semi-elective one with medical management
  • Note Hartmann's would be reversed in about a year if faecal contamination, or 3-4/12 if not.

Management of other complications

Obstruction

• • Fibrosis of colonic wall, leading to stricture
  • Presents with insidious symptoms and a partial obstruction
  • Needs operation
    • Partial obstruction - aim elective resection
    • Complete obstruction - emergency surgery
  • Consider cancer as similar appearance on CT. Exclude with colonoscopy prior to OT if possible.

Fistula -  require surgery generally

• • Occur due to development of an abscess that decompresses into a neighbouring organ
  • Colovesical fistula:
    • Most common type, especially in men.
    • Generally to dome of bladder.
    • Present with recurrent UTIs, which are generally polymicrobial. Pneumaturia and faecaluria may be present.
    • Rarely need an emergency operation. If needing to do something emergently, probably better off diverting as a bridge to elective resection.
    • Poppy seed test is diagnostic in 95% (actually much better than cystoscopy or CT). CT shows air in bladder in absence of prior instrumentation. Can generally be seen on cystoscopy.
    • Settle sepsis, arrange colonoscopy and flexible sigmoidoscopy (+/- ureteric stenting) and fix with segmental resection. Don't need to do anything to close bladder side usually. Leave IDC 72 hours.
    • Non-operative management is usually a fruitless endeavour with the eventual development of multi-resistant UTIs that have to be palliated.
  • Colovaginal fistulae
    • Almost exclusively in post-hysterectomy women
    • Present with vaginal discharge and passing air per vagina
    • Can present immediately after an acute perforation with sudden release of fluid from vagina, which stops spontaneously in most cases. If it doesn't they could have a diverting loop ileostomy, as a bridge to elective resection.
  • Colocutaneous
    • Usually at site of a previous percutaneous abscess drainage
    • Usually don't need emergency surgery - investigate with colonoscopy and appropriate imaging to exclude Crohn disease
    • Need to resect the colon and tract with primary anastomosis
  • Coloenteric
    • Usually require resection and primary anastomosis

Bleeding

• • See LGIB topic

Trials

• LOLA trial (2015) - purulent perforated diverticulitis (H3) was randomised to either laparoscopic lavage or Hartman's procedure
  • Increased morbidity (primarily re-operation) in the lavage group
• SCANDIV trial (2015) - also found a high rate of re-operation in lavage, concluded that lavage is inferior to resection
• DILALA trial (2018) - Hinchey III randomised to lavage vs Hartman's
  • Reduced risk of re-intervention (including stoma reversal) in lavage group, with same length of stay
  • Authors concluded that lavage is a safe alternative
• DIRECT trial (2019) - ?surgery for recurrent left-sided diverticulitis
  • 5-year improved QoL in surgery group, despite 11% anastomotic leak rate and 15% re-intervention rate

Colonoscopy should always be considered

• Follow-up colonoscopy for patients with abscess/perforation in 6-12 weeks (although data is scant on timing)
• World Society of Emergency Surgery says no follow-up colonoscopy for first episode uncomplicated patients - although this is controversial. Sabiston recommends it.
• 1-3% reportedly will have a cancer of some description, but these are almost all found in complicated diverticulitis

Prognosis

• Following non-operative management of a first attack, about one-third will have another attack, after which one-third will have a third attack
  • Most patients do not develop recurrent diverticulitis
• Prior uncomplicated attacks don't predict more quantity or severity of recurrence - therefore not a useful indication for elective surgery
• Recurrent diverticulitis is usually not more severe